Dissolved air flotation (DAF) is a water treatment process that clarifies wastewaters (or the waters) by the removal of suspended matter such as oil or solids. The removal is achieved by dissolving air in the water or wastewater under pressure and then releasing the air at atmospheric pressure in a flotation tank basin. The released air forms tiny bubbles which adhere to the suspended matter causing the suspended matter to float to surface of the water where it may then be removed by a skimming device.


GF Type combined DAF consists of flotation tank, dissolved air system, reflux pipe, dissolved air released system, skimmer (Based on customer needs, there are combined type, traveling type and chain-plate type to choose), electric cabinet and so on.

Air flotation separation technology dissolves air into water at certain working pressure. In the process, pressurized water is saturated with dissolved air and is discharged into a flotation vessel. The microscopic air bubbles produced by released air attach to suspended solids and float them to the surface. forming a sludge blanket. Finally, it complete purifies the water.

Air flotation technology plays an important in solid-liquid separation. (simultaneously reduce COD, SOD, chroma, etc). Firstly, mix flocculating agent into raw water and stir thoroughly. After the effective retention time (lab determines the time, dosage and flocculation effect), the raw water enters into the contact zone where microscopic air bubbles adhere to the floc and then flows into the separation zone. Under the buoyancy effects, the tiny bubbles float the flocs to the surface, forming a sludge blanket. A skimming device removes the sludge into the sludge hopper. Then the lower clarified water flows into the clean-water reservoir through the collecting pipe. Some of water are recycled to the flotation tank for the air dissolving system, while others will be discharged.


Dissolved air flotation is very widely used in treating the industrial wastewater effluents from oil refineries, petrochemical and chemical plants, natural gas processing plants, paper mills, general water treatment and similar industrial facilities. Such as electroplating, food, slaughtering, brewing, tanning, printing, and dyeing, paper making.


  • Small footprint, lower energy consumption; easy operation and simple management.
  • High efficiency of air dissolving, stable treatment effects;
  • This unit uses our GFA dissolved air System with ingenious structure. Its efficiency of air dissolving can reach up to 90%. Compared with traditional air system, our new dissolved air System has about one-fifth volume. What’s more, it has strong anti-clogging capacity
  • Use chain-plate skimmer, stable operation and high efficiency of scraping.